Insight into the Epidemiology of Leptospirosis: A Review of Leptospira Isolations from “Unconventional” Hosts

Abstract

Leptospirosis is a re-emerging worldwide zoonotic disease. Even though the primary serological test for diagnosis and surveying is the microscopic agglutination test (MAT), isolation remains the gold-standard test to detect Leptospira infections. The leptospirosis transmission is linked to maintenance and accidental hosts. In the epidemiology of Leptospira some serovar are strictly related to specific maintenance hosts; however, in recent years, the bacterium was isolated from an even wider spectrum of species. The aim of this review is to report the isolation of Leptospira strains in animals which could be recognized as “unconventional” hosts, analyzing studies from 1960 to 2020 that highlighted the Leptospira isolation. This scientific literature aimed to provide evidence of infection in several animal species including of the Carnivora, Didelphimorphia, Rodentia, Cetacea, Cingulata, Afrosoricida, Chiroptera and Primate orders, as well as in Reptilia and Amphibia classes. In conclusion, the spreading of Leptospira is attention-worthy because the infection could occur in all the animal species ranging in a specific area. Further screening and isolations are needed to collect all necessary data to gain a complete understanding of leptospirosis epidemiology and its modifications.

New Insights on Leptospira Infections in a Canine Population from North Sardinia, Italy: A Sero-Epidemiological Study

“…Leptospirosis is a cosmopolitan zoonosis caused by bacteria belonging to the genus Leptospira, which is well known for infecting humans and a wide variety of domesticated and wild vertebrates [1]. Leptospira species have been described also in several 'unconventional' hosts [2] such as reptiles [3], amphibians [4], and cetaceans [5,6], as well as from many other different orders, suggesting that most microbial diversity in hosts is largely unknown. Humans can become infected by direct exposure to infected animals and their products (urines or body fluids) [7].…”

Exposure of Free-Ranging Wild Animals to Zoonotic Leptospira interrogans Sensu Stricto in Slovenia

“…Wildlife diseases occur in numerous forms in a wide range of species and populations around the globe. Leptospirosis is a zoonosis of global importance, affecting many species of wild and domestic animals, as well as humans [ 1 , 3 ]. Leptospira spp.…”

“…Infections with Leptospira spp. can affect not only people in exposed professions (i.e., veterinarians, trappers, abattoir workers, farm workers, hunters, animal shelter workers and scientists and technicians involved with animals in laboratories or in the field) but also people who work with marine mammals, fishmen, researchers, wildlife rehabilitators, animal trainers and zoological park workers [ 3 ]. A study conducted in Austria [ 29 ] reported that hunters in particular are exposed to zoonotic agents, including leptospires, probably through the direct contact of abraded skin or mucous membranes with the tissues, blood or urine of infected animals [ 30 , 31 ].…”

Leptospirosis at human-animal-environment interfaces in Latin-America: drivers, prevention, and control measures

“…The bacteria resides in the kidneys of these animals, and they commonly do not show clinical signs of the disease. The presence of Leptospira in wild animals including mammals (mainly rodentia), birds, reptiles, and amphibians, have been thoroughly reviewed by Vieira et al (2018) and Cilia et al (2021), where many unconventional hosts were identified in North and Latin-American countries. Although wildlife has a real role in the Leptospira transmission cycles, information is still scarce for many regions of the world (Vieira et al, 2018).…”

“…Leptospirosis, caused by spirochetal bacteria of the Leptospira genus, is considered the most widely distributed zoonotic disease on the planet (Samsudin et al, 2018). Leptospira has been isolated in many vertebrate taxa, including mammals, birds, amphibians, reptiles, and fish (Viera et al, 2018;Cilia et al, 2021), and has shown genetic heterogeneity. Leptospirosis represents a disease associated with poverty and low sanitation environments, both in rural and urban communities, as well as in livestock production areas, where close interaction with animals could favor the leptospirosis spread.…”